1. Field of the Invention
The present invention relates to a telephone system quipped with a transfer function.
2. Description of the Related Art
In recent years, a telephone service in a company and a business office has become widely diversified by using an Internet protocol (IP) telephone. Particularly, in a session initiated protocol (SIP) telephone system, a user itself can set a variety of functions to a telephone terminal (for example, refer to, Jpn. Pat. Appln. KOKAI Publication No. 2002-152224).
The SIP telephone system has necessary functions and unnecessary functions in accordance with a user's preference. In the SIP telephone system, the user can use favorite telephone functions by individually combining them for each user. This is because an application server for managing the telephone functions manages the functions by associating a user ID with identification information of a telephone terminal. The user can invoke and use personal functions from any telephone terminal by using this management function. In contrast, a plurality of users can respectively use a single telephone terminal as a personally set telephone terminal.
By the way, a transfer function is known in a system of this kind. The transfer function transfers an incoming call to a previously set other place (conference room, etc.) when a user is not present at an original place (office, etc.). A telephone terminal at a transfer destination is set from a telephone terminal at a desk of the user before the user moves away from the desk. However, if the user forgets to release the transfer function after coming back to the desk, the telephone terminal at the desk is left in a state not to receive an incoming call. As just described, there is a problem that in the transfer function capable of being set the transfer destination from the telephone terminal by the user, the original telephone terminal is left in the state not to receive the incoming call if the user forgets to release the transfer function.